This is useful when the model name has been updated an it's used in the SEO optimized URL. In other words this will automatically correct the URL with a proper redirect when e.g. a crawler visits an old URL.

Is this SEO Extension will do the all the SEO things, I means its enough right? does it need any thing else for SEO purpose ? how to make the regular updation of the files made easy ? is it right to put one crone file and and update the file ?

Google says frequent updation of files will be an advantage in case of SEO. Updation files means, actually what kind of updation, if we changed the file name its an updation right ? if we changing the content it would be an updation right ? if we cahnge the content of a home page (i mean index page ) by executing one crone file in my server, i mean i will we done on every day morning at a constant time, which will open the index.php file, and edit the index.php by removing somelines, and then adding some lines (some times it may the same). have you got the point ? does it works fine in case of SEO ? this is my question ...!!

Now I understand what you're getting at. Updating of the content is done when e.g. the Googlebot crawls your site, if content has changed it will notice it. However, if you use the name in the URL and you change the name, then the old URL will be incorrect and we need to tell the crawlers that the page has been moved. This can be done with the SeoFilter.